Evaporative coolers

ABSTRACT

An evaporative cooler has a housing mounted within the roof space of a pitched roof with the housing inlet, which mounts evaporative cooling pads, lying at or adjacent to the plane of the roof. This construction avoids the unsightly protrusion normally associated with roof-mounted evaporative coolers.

The present invention relates to an evaporative cooler and moreparticularly to an evaporative cooler for use in a ducted coolingsystem.

Conventionally, an evaporative cooler for use in a ducted cooling systemcomprises a large box-like housing installed on the roof of a buildingand includes an outlet for cooled air which extends through the roof forconnection to ducting installed within the roof space for distributionof the cooled air to selected parts of the interior of the building. Thehousing contains evaporative pads through which external air is drawn bya fan mounted within the housing, for discharge through the outlet andducting connected thereto. Evaporative pads of relatively large area areneeded to obtain the required volume of cooled air and as a result, theoverall housing of the cooler is relatively large. Accordingly, theinstallation of an evaporative cooler particularly on the pitched roofof a domestic dwelling where, typically, the housing has a significantprojection over the roof line, can be very unsightly. Moreover, a fan ofhigh capacity is required to generate the requisite air flow and thiscan result in substantial noise generation externally of the housingparticularly when the cooler is operating close to its maximum capacity.This noise generation can be quite troublesome in an urban situation andcan result in nuisance to near neighbours.

According to the present invention there is provided an evaporativecooler having a housing adapted to be installed within the roof space ofa pitched roof, said housing having an air inlet associated with one ormore evaporative pads defining an air-permeable cooling means, means forsupplying water to the or each pad, and a fan for drawing external airinto the housing via the air-permeable cooling means and for dischargingthe air thereby cooled via an outlet, wherein the housing is soconfigured that the air-permeable cooling means is closely adjacent theexternal surface of the pitched roof.

Further according to the invention, there is provided an evaporativecooler having a housing adapted to be installed within the roof space ofa pitched roof, said housing having an air inlet associated with one ormore evaporative pads defining an air-permeable cooling means, means forsupplying water to the or each pad, and a fan for drawing external airinto the housing via the air-permeable cooling means and for dischargingthe air thereby cooled via an outlet, wherein the housing is soconfigured that when the unit is installed there is no substantialprojection of the air-permeable cooling means beyond the externalsurface of the pitched roof.

Still further according to the invention, there is provided anevaporative cooler having a housing adapted for installationsubstantially within the roof space of a pitched roof, said housinghaving an inlet adapted to lie at or adjacent to the plane of the roof,one or more evaporative pads mounted to the inlet, the or each paddefining an air-permeable cooling means, means for supplying water tothe or each pad, and a fan for drawing external air into the housing viathe air-permeable cooling means and for discharging the air therebycooled via an outlet.

Still further according to the invention, there is provided anevaporative cooler installation mounted within the roof space of apitched roof of a building, said installation including an evaporativecooler having a cooler housing mounted between rafters of the pitchedroof, said housing being substantially wholly within the roof space andcarrying a fan for drawing external air into the housing via one or moreevaporative pads defining an air-permeable cooling means and fordischarging the air thereby cooled via an outlet from the housing, andsaid housing also carrying a water reservoir and a pump for feeing waterfrom the reservoir to the or each pad and forming means for supplyingwater to the or each pad, whereby said fan, water reservoir, and pumpare also within the roof space, wherein the housing mounts theair-permeable cooling means adjacent the external surface of the pitchedroof.

Still further according to the invention, there is provided anevaporative cooler installation mounted within the roof space of apitched roof of a building, said installation including an evaporativecooler having a cooler housing mounted between rafters of the pitchedroof, said housing being substantially wholly within the roof space andcarrying a fan for drawing external air into the housing via one or moreevaporative pads defining an air-permeable cooling means and fordischarging the air thereby cooled via an outlet from the housing, andsaid housing also carrying a water reservoir and a pump for feedingwater from the reservoir to the or each pad and forming means forsupplying water to the or each pad, wherein the housing mounts theair-permeable cooling means such that there is no substantial unsightlyprojection of the air-permeable cooling means beyond the externalsurface of the roof.

In one form the air-permeable cooling means is substantially planar andmay be arranged to lie parallel to the plane of the roof or flush withthe roof; alternatively it may be inclined through a small angle to theplane of the roof and/or project slightly from the plane of the roofwhile still avoiding unsightly protrusion.

Water can be applied to the or each evaporative pad of the planarair-permeable cooling means by spraying or drip feeding water onto theexternal surface of the pad. The base of the housing defines or containsa reservoir for supply of water to the pads and also to receive waterdraining from the pads and to direct this to the reservoir. As such, thereservoir will also catch any rain water penetrating the pads when thecooler is not in use. In practice, a high level overflow pipe will beincorporated to discharge excess water from the reservoir.

In an alternative form the evaporative pads forming the air-permeablecooling means may be arranged in an angular array one inclined relativeto another while still lying close to the plane of the roof to avoidsignificant unsightly protuberance. In this form the pads may be mountedwholly within the inlet portion of the housing to avoid substantiallyany protrusion above the plane of the roof, the pads having a relativelyupright orientation so that water can be fed to troughs at the upperedges of the pads to flow downwardly through the pads in the lengthdirection thereof. In this form also, the base of the housing defines orcontains a reservoir for supply of water to the pads and also to receivewater draining from the pads and to direct this to the reservoir.Although it is particularly preferred for the pads to be mounted so thatthere is substantially no protrusion above the plane of the roof,nevertheless a configuration in which the inlet to the housing extends asmall distance above the plane of the roof would be feasible as thiswould still avoid any significant unsightly protrusion.

In practical embodiments of the invention, the housing is of a wedgeshape of a width to fit between rafters of the pitched roof and with aninclined upper side which extends substantially in or parallel to theplane of the roof in the longitudinal direction of the rafters, theupper side including or forming the inlet to which the air-permeablecooling means is mounted. To facilitate adaptation of the cooler to suita wide range of roof pitch angles the upper part of the housingincluding the air inlet is adjustable in inclination relative to a lowerpart of the housing, for example by being pivotally mounted thereto orbeing connected thereto by flexible sheet material.

The embodiments of the invention will now be described by way of exampleonly with reference to the accompanying drawings in which:

FIG. 1 is a schematic cross section showing an evaporative cooler inaccordance with the invention mounted within the roof space of a pitchedroof;

FIG. 2 is shows schematically the installation as viewed from theoutside of the roof; and

FIG. 3 is a schematic cross section through the housing of the cooler toshow integral flashing formed around the outer side of the housing;

FIGS. 4 to 6 are schematic cross sections showing in greater detailfurther embodiments of the invention.

With initial reference to FIGS. 1 to 3, an evaporative cooler comprisesa main housing 2 adapted for installation within the roof space 4 of apitched roof, rather than externally of the roof space as isconventional. The housing 2 is of rectangular cross-section of a widthsuch that the housing can fit between two adjacent rafters of the roofstructure subject to probable modification of the roof structure toremove part of one or possibly even two intermediate rafters to providethe requisite size. The housing 2 is substantially of wedge-shapeoverall such that the outer side of the housing which carries theevaporative pads 6 extends along the width of the housing and also alongthe length of the housing in such a way that it lies substantiallywithin the plane of the pitched roof. Accordingly, the evaporative pads6 are arranged in a planar array which is also substantially within theplane of the roof or parallel to the plane of the roof in closeproximity thereto.

Most domestic dwellings designed in accordance with current buildingregulations will have rafters at approximately the same spacing and withpart of just a single intermediate rafter removed, a housing 2 having awidth of approximately 550 mm can be accommodated and this should proveadequate for most installations as will be explained. The housing can besupported directly or indirectly from the rafters. It is to be notedthat even in most installations involving conventional coolersexternally mounted on the roof, an aperture having a width of similardimension is required to permit passage of the outlet duct from thecooler into the roof space.

In the particular embodiment shown the wedge-shaped housing 2 has abottom wall 8 which extends with a slight inclination towards the roofgutter line and a vertical end wall 12 mounting a duct-like extension 14forming a housing within which a fan is mounted, the fan housing 14having an inlet communicating with the interior of the main housing 2and outlets 16 for connection to appropriate ducting within the roofspace 4. The main housing 2 also has a system for applying water to theouter surface of the evaporative pads 6. In one form, this can involvethe spraying of water onto the pads 6 from jets arranged along at leastone longitudinal edge of the planar array of pads 6, or possibly alongboth longitudinal edges and/or the upper or lower end edges of the padarray. The water may be sprayed from individual spray jets carried by awater manifold extending along one or more of the edges of the outerside of the main housing 2, with the spray jets being so positioned asto ensure adequate water penetration over the entire face of the padarray for maximum cooling effect. The jets may alternatively be formedby slots or holes in the manifold.

Instead of spraying the water onto the pad array, the water may bedripped onto the pad array by drip emitters carried by or formed in themanifold by holes or slots. When a drip system is used several dripmanifolds may span across the width or length of the pad array, thepitch spacing of the drip emitters and manifolds being such as to ensurewater penetration across the entire face of the pad array. A similarmanifold arrangement could be used with spray jets.

The bottom part of the main housing 2 will form or contain a reservoirfor water to be fed to the spray or drip system by a suitable pumpmounted within the housing. Surplus water from the pads will also draininto the reservoir as will any rain falling on the roof and penetratingthe evaporative pads when the cooler is not in use. During operation ofthe cooler, the reservoir will be filled with water from the mainssupply via a suitable float valve. A valve-controlled outlet permitsdischarge of water from the reservoir as required, with an overflowoutlet automatically effecting discharge when the water within thereservoir reaches a predetermined level, for example as may occur duringwinter months subject to rain fall with the cooler inactive.

Advantageously, the housing 2 is formed with flashing 20 (see FIG. 3)around the perimeter of its outer side. The flashing along the twolongitudinal edges and upper edges is designed to sit under the roofingmaterial and the flashing along the lower edge is formed approximately50 mm higher to sit over the top of the roofing material to allow forrain water run off. Preferably, the housing 2 including the flashing ismoulded from a suitable plastic material. As shown in FIG. 3, theflashing is preferably formed with a return edge 20 a of U-shape toprevent water penetration by capillary action. Flashing as described andillustrated is in a configuration to suit a tiled roof. Flashing for usewith a metal roof will be of a different configuration as will be wellunderstood by those experienced in roofing construction.

Advantageously, one or more of the vertical walls of the housing 2 hasinspection panels which are removable to permit access from within theroof space for fill maintenance of the cooler including the sprays ordrip emitters as well as internally mounted components such as the fanand pump, and replacement of the pads. The ability to effect fullmaintenance from within the roof space is of significance as work safetyrequirements may require the use of safety harnesses and safety rails ifwork is to be undertaken from the external surface of the roof.

Externally of the evaporative pads 6, the housing 2 may carry a gridstructure 42 sufficient to prevent an adult person on the roofaccidentally standing on the pads and falling into the housing; it ishowever to be understood that the design of such a grid structure shouldensure that there is no substantial impediment to air flow through thepads from the outside.

Current conventional evaporative coolers for domestic installations tendto have an evaporative pad area of from about 1 m² for smaller units to2 m² for larger units. With the construction proposed herein with a mainhousing width of approximately 550 mm, an evaporative pad area ofapproximately 1 m² can be achieved by a housing in which the length ofits inclined outer side is approximately 2 meters and a pad area of 2 m²can be achieved with a wall of approximately 4 meters; even a length of4 meters can readily be accommodated within the roof structure of mostdwellings.

FIG. 4 shows in somewhat greater detail an embodiment of the inventionin which the bottom wall 30 of the main housing 2 is inclined from backto front and is formed at its front end with a sump 32 into which waterdrains from within the housing and which also acts as a reservoir forwater to be supplied to the evaporative pads. The sump 32 houses a waterpump 34 for feeding water to the evaporative pads or alternatively thepump 34 may be mounted externally of the sump 32, with the inlet to thepump 34 leading from the sump 34. Fresh water is fed into the sump 32via a water feed line controlled by a float valve (not shown) or otherlevel-responsive valve. An overflow outlet 36 and a valve-controlleddrain outlet 37 lead from the sump 32. The fan housing 14 leads from thevertical end wall 12 adjacent the bottom wall 30 of the main housing,with the outer end of the fan housing 14 being connected to suitableducting in conventional manner for distribution of the cooled air withinthe building. An inspection opening is provided in at least one of thetwo side walls of the main housing 2 and is accessible after removal ofa cover 38 to provide access to the interior of the cooler to facilitateservicing from internally of the roof structure.

Flashing integrally formed with the main housing 2 is shown at 20 andthe housing 2 preferably carries a rain water diverter 40 of V-shapedconfiguration moulded into the upper flashing 20 so that rain waterflowing down the roof above the cooler is diverted to flow at eitherside of the cooler rather than entering the cooler via the open upperside as may otherwise arise with substantial downpours of rain.

A safety grid 42 capable of carrying the weight of an adult person ismounted on the upper side of the housing 2 above the evaporative pads.

As shown in FIG. 4 the evaporative pads (designated 6 a, 6 b in thisfigure) are positioned in an angular array in the upper inlet portion ofthe housing 2 so that each pad has an outer edge adjacent the plane ofthe roof and an inner edge located further within the interior of thehousing 2, with each pad being inclined to the plane of the roof. Thisconfiguration permits a substantial increase of pad area for a givenlength and width of housing in relation to that provided by the planarpad array shown in FIG. 1. It also facilitates water supply anddistribution to the pads. Each pad has in this configuration a shorterlength and a greater inclination to the vertical so that the pad can besupplied with water fed to a trough or channel extending along the upperedge of the pad with the water flowing downwardly by gravitationalaction along the length of the pad in a similar manner to that whichoccurs in conventional evaporative coolers with vertical pads.

Water can be supplied to each pad 6 a, 6 b through a separate troughextending along the upper edge of the pad in substantially conventionalfashion, or alternatively a single trough can be associated with eachpair of adjacent pads in the zone at which the upper edges of the twoadjacent pads meet.

It will be seen in the configuration of FIG. 4, that the pads consist ofalternating shorter pads (those designated 6 a) and longer pads (thosedesignated 6 b) whereby when the cooler is installed, each pad will beinclined at approximately the same angle to the vertical as will beapparent from FIG. 4. Most pitched roofs in modem housing constructionhave a pitch angle within the range of approximately 22° to 30°. In onepractical form of the invention the pads 6 a, 6 b are configured to havethe same angle of inclination to the vertical (approximately 13°) wheninstalled within a roof having a pitch angle of 26°. This configurationwill suit the standard range of pitch angles just mentioned and althoughthis will mean that in installations where the pitch angle is other thana 26° pitch angle, the two sets of pads will not have the same angle ofinclination to the vertical, this is of no consequence to thefunctioning of the cooler as both sets of pads will still have aninclination to the vertical sufficient to allow the flow of waterdownwardly through the pads from the troughs at the upper edges of thepads.

It will be appreciated that with this angular array of pads in the zonewhere one pad meets an adjacent pad at its upper or lower edge, a sealdoes need to be formed so that incoming air does not bypass the pads atthat zone. If the adjacent pads are in direct edge to edge contact, theedge portions can be chamfered to ensure contact over a sufficientheight to provide an effective seal, rather than achieving substantiallyjust a line contact. Alternatively a sealing strip or other form of sealstructure can be incorporated between the adjacent pads in the zonewhere they meet.

With an evaporative cooler of the form shown in FIG. 1 and FIG. 4 inwhich the evaporative pads are not arranged vertically it is likelythat, in use, some water will drip from the undersurface of theevaporative pads into the interior of the main housing 2. Although someof this dripping water is likely to fall directly to the bottom of thehousing for collection and re-use, nevertheless it is likely that underthe high rate of induced air flow through the housing, some of the waterdroplets may be entrained within the air flow and may be carried out bythe air flow into the ducting in which case it is likely that at leastsome of those entrained water droplets will settle out from the air flowinto the ducting perhaps forming small pools of water within the ductingor may even be retained within the air flow discharged into a spacebeing cooled. To avoid this phenomenon, the cooler advantageouslyincorporates a device positioned in the path of the air flow exiting thehousing to remove water droplets which may be suspended in the air flow.In one form as shown, this device comprises an array 50 of spaced vanesthrough which the cooled exiting air flow will pass, the slightinclination of the vanes causing diversion of the air flow direction atleast to an extent sufficient to cause the major amount of suspendedwater droplets to settle out onto the surface of the vanes duringpassage therethrough, with the water dripping from these vanes onto thebottom wall of the housing 2 for collection. Alternatively, the devicecan comprise a pad of the same type as that used for the evaporativepads so that as the exiting cooled air passes through that pad it willact rather in the manner of a filter to collect water droplets whichmight be suspended within the air flow. Depending on the humidity of thecooled air, water collected on this pad might itself be evaporated andabsorbed into the air flow, but if not, it will flow downwardly alongthe pad to be collected on the bottom wall of the housing. As shown, thearray 50 of vanes (or alternatively the pad) is positioned adjacent theend wall 12 of the housing 2, although other positioning which providesthe same effect could be provided.

The detailed housing structure just described including rain waterdiverter 40 and droplet removal device is equally applicable to theembodiment described with reference to FIGS. 1 to 3 in which theevaporative pads lie in a planar array substantially parallel to theplane of the roof.

FIG. 5 shows a cooler of the general type shown in FIG. 4, but in whichan upper part 2A of the housing which carries the pads 6, water feedsystem, flashing 20, rain water diverter 40 and safety grid 42 ispivoted to a lower part 2B of the housing including the sump 32,inspection opening 38 and fan housing 14. The pivotal connection isprovided by a horizontal pivot 52 adjacent the forward wall of thehousing so that the upper part 2A of the housing can be swung into aninclination to suit the particular pitch of the roof into which thecooler is being installed. This is of particular benefit when the cooleris being installed within a roof having a pitch outside of the normalrange previously discussed. The walls of the housing parts 2A and 2B arein overlapping relation throughout the range of pivotal movement. Therear end walls 12 a, 12 b of the pivotal upper housing part 2A and ofthe lower housing part 2B are of arcuate form of a radius centred aboutthe axis of pivot 52 to facilitate close contact between these wallparts throughout the range of pivotal movement of the upper housing part2A. When the upper housing part 2A has been adjusted to the correctangle for installation it is secured in position relative to the lowerhousing part 2B by screws extending through the overlapping side and endwalls of the two housing parts and also the joint between theoverlapping walls is preferably sealed with a suitable sealant to ensurethat that air is not drawn into the housing between the upper and lowerhousing parts. Although FIG. 5 shows the evaporative pads 6 arranged ina substantially planar array within or substantially parallel to theplane of the roof, the pads may be arranged in an angular array asdescribed in relation to FIG. 4.

FIG. 6 shows an alternative form of housing which facilitates adjustmentfor the pitch angle of the roof in which the upper housing part 2Bcarrying the pads 6, flashing 20, water distribution system, safety grid42, and rain water diverter 40 is connected to the lower housing 2A partby flexible sheet material 60 such as sheet plastic. In theconfiguration shown, the flexible sheet material is of concertina formalthough that is not essential and the sheet material can simply be arobust flexible plastics sheet capable of accommodating the requiredpositioning of the upper housing part 2A, with the sheet being folded toabsorb any excess sheet material arising when installed. Although therewill not in this case be a rigid connection between the upper and lowerhousing parts 2A, 2B, each housing part will be individually fixed tothe roofing structure on installation and therefore no relative movementwill occur between these parts when installed. The planar array of pads6 shown in FIG. 6 may be replaced by an angular array such as shown inFIG. 4.

The embodiments of FIGS. 4 to 6 are installed between adjacent raftersof the roof structure in the manner previously described in relation toFIG. 1.

Although in the embodiments shown in FIGS. 1, 5 and 6 using a planararray of pads, the pads are positioned substantially in the plane of theroof or in proximity thereto, with the water being supplied to the padsby sprays and/or drip emitters directed onto the external surface of thepads, it may be desirable for the planar array to be mounted within theinlet portion of the housing below the roof line by an extent sufficientto ensure the spray/drip emitters are more shielded from the effects ofexternal wind.

With the constructions described, the array of evaporative pads liessubstantially within the plane of the pitched roof or closely adjacentthereto. Although the array of pads is able to receive substantiallyunrestricted air flow from outside of the roof space and which isnecessary for effective operation, the unsightly projection ofconventional coolers is avoided; the presence of the cooler may not evenbe perceptible from the ground. The fan itself is incorporated in thepart of the housing within the roof space; although some fan noise willinevitably still exist, nevertheless the external noise levels should besubstantially diminished in relation to conventional externally mountedcoolers. Also, the externally mounted housings of conventionalexternally mounted coolers when formed from plastics material aresubject to degradation arising from UV exposure and this does, in time,result in maintenance problems. In the preferred embodiments of thepresent invention, the plastics housing of the cooler is not exposed.

Conventional evaporative coolers have to be installed after completionof the building or at least after completion of the roof structure. Thecooler in accordance with the preferred embodiment of the invention canbe installed from inside of the building prior to application of theroofing material and prior to installation of the ceiling and insulatingmaterial. Accordingly, the installation can be effected without the needto fit safety railing on the roof line thereby reducing labour costs.The incorporation of the integral flashing around the housing alsofacilitates a substantial cost saving in installation.

The embodiments has been described by way of example only andmodifications are possible within the scope of the invention.

Throughout this specification and claims which follow, unless thecontext requires otherwise, the word “comprise”, and variations such as“comprises” or “comprising”, will be understood to imply the inclusionof a stated integer or group of integers or steps but not the exclusionof any other integer or group of integers.

1. An evaporative cooler having a housing adapted to be installed withina roof space of a pitched roof, said housing having an air inlet whichis inclined in such a manner as to extend substantially parallel to apitched plane of the pitched roof when installed, at least twoevaporative pads mounted in the housing and defining an air-permeablecooling means associated with the inlet, means for supplying water tothe at least two pads, and a fan for drawing external air into thehousing via the air-permeable cooling means and for discharging the airthereby cooled via an outlet of the housing, wherein the housing is soconfigured that when installed within the roof space the inclined airinlet is closely adjacent the external surface of the pitched roof andwherein the at least two pads defining the air-permeable cooling meansare arranged within the housing beneath the inlet in an angular array,one inclined relative to another, to define a zig-zag configuration. 2.An evaporative cooler according to claim 1 wherein the housing isconfigured so that the inlet is inclined in such a manner as to extendsubstantially parallel to the pitched plane with the inlet lying closelyadjacent to the external surface of the roof to avoid any substantialprojection of the housing beyond the external surface of the roof, andthe air-permeable cooling means is mounted within the housing so as tobe positioned substantially wholly beneath the level of the externalsurface of the roof.
 3. An evaporative cooler according to claim 1wherein the housing is so configured that when the unit is installedthere is no substantial projection of the air-permeable cooling meansbeyond the external surface of the pitched roof.
 4. An evaporativecooler according to claim 1, wherein the air-permeable cooling meansformed by the at least two pads is substantially planar in form and ismounted within the housing in an inclined configuration so as to liesubstantially parallel to the inlet.
 5. An evaporative cooler accordingto claim 4, wherein the water supply means includes spray and/or dripemitters configured to discharge water onto an upper outwardly-facingsurface of the at least two pads defining the air-permeable coolingmeans.
 6. An evaporative cooler according to claim 1, wherein theinclination of the individual pads within the zig-zag configuration issuch that water supplied by the water supply means to an upper edge ofeach pad will flow downwardly through the pad in a length directionthereof.
 7. An evaporative cooler according to claim 1, wherein themeans for supplying water to the air-permeable cooling means comprises areservoir at a base of the housing, and the base of the housing is soconfigured that surplus water discharged from the at least two pads intoan interior of the housing is directed into the reservoir for re-use. 8.An evaporative cooler according to claim 1, wherein the housing has aninclined outer wall in which the inlet is formed, the outer wallincluding flashing for cooperation with the roof.
 9. An evaporativecooler according to claim 8, wherein the flashing is integrally formedwith the housing.
 10. An evaporative cooler according to claim 8,wherein the flashing includes a rain water diverter for diverting waterflowing down the roof from above the cooler to substantially preventsuch flowing water from flowing into an interior of the housing via theair-permeable cooling means.
 11. An evaporative cooler according toclaim 1, having within an interior of the housing, means for removingwater droplets which may be entrained within a flow path of the cooledair.
 12. An evaporative cooler according to claim 11, wherein thedroplet removal means comprises an array of vanes positioned within theflow path of the cooled air.
 13. An evaporative cooler according toclaim 11, wherein the droplet removal means comprises an air-permeablepad positioned within the flow path of the cooled air.
 14. Anevaporative cooler according to claim 1, wherein the air-permeablecooling means is mounted to an upper part of the housing including theinlet, said upper housing part being movable prior to installation ofthe cooler relative to a lower housing part which includes the outlet,the movement between the upper housing part and lower housing partenabling the housing to be adjusted to suit a pitch of the roof intowhich the cooler is being installed.
 15. An evaporative cooler accordingto claim 14, wherein the upper housing part is pivotally attached to thelower housing part to enable the upper housing part to be swung relativeto the lower housing part to adjust an angle of inclination of the upperhousing part to suit the pitch of the roof.
 16. An evaporative cooleraccording to claim 15, wherein the upper and lower housing parts havewalls which lie in overlapping relationship throughout a range ofmovement of the upper housing part relative to the lower housing part.17. An evaporative cooler according to claim 15, wherein the upperhousing part is sealed relative to the lower housing part by a flexiblesheet material which permits the relative movement between the housingparts.
 18. An evaporative cooler according to claim 17, wherein theflexible sheet material is of concertina like form.
 19. An evaporativecooler according to claim 1, wherein the housing carries above theair-permeable cooling means a structure to prevent a person on the rooffrom stepping onto the air-permeable cooling means and falling into theinterior of the housing.
 20. An evaporative cooler installationcomprising: a cooler housing having a housing inlet and configured to bemounted within a roof space of a pitched roof; and at least twoevaporative cooling pads associated with the housing inlet, wherein thehousing inlet is inclined to lie substantially parallel to a pitchedplane of the pitched roof in close proximity thereto when theevaporative cooler installation is installed within the roof space ofthe pitched roof; and the pads are arranged within the housing in anangular array, one inclined relative to another, to define a zig-zagconfiguration.
 21. An evaporative cooler installation according to claim20 wherein the cooler housing is mounted substantially wholly within theroof space of the pitched roof with the housing inlet for entry ofexternal air being inclined so as to lie substantially in the pitchedplane of the pitched roof, the at least two evaporative cooling padsbeing mounted within the housing substantially wholly beneath thepitched plane of the pitched roof such that external air flow is drawninto an interior of the cooler housing via the housing inlet and the atleast two evaporative cooling pads for discharge from an outlet of thecooler housing.
 22. An evaporative cooler installation according toclaim 20 wherein the cooler housing is configured to be mounted betweenrafters of the pitched roof, said cooler housing carrying a fan fordrawing external air into the cooler housing via at least twoevaporative pads defining an air-permeable cooling means and fordischarging the air thereby cooled via an outlet from the coolerhousing, and said cooler housing also carrying a water reservoir and apump for feeding water from the reservoir to the at least twoevaporative pads and forming means for supplying water to the at leasttwo evaporative pads, wherein the cooler housing mounts theair-permeable cooling means such that there is substantially noprojection of the air-permeable cooling means beyond an external surfaceof the pitched roof.
 23. An evaporative cooler installation according toclaim 20, further comprising: means for supplying water to each padwherein the inclination of the individual pads within the zig-zagconfiguration is such that water supplied by the water supply means toan upper edge of each pad will flow downwardly through the pad in alength direction thereof.
 24. An evaporative cooler installationaccording to claim 20 having an air-permeable pad within the interior ofthe housing downstream of the cooling pads to remove water dropletswhich may be entrained within a flow path of the cooled air.
 25. Anevaporative cooler installation according to claim 20 wherein the coolerhousing is mounted substantially wholly within the roof space.
 26. Anevaporative cooler installation according to claim 25 wherein the coolerhousing includes opposed substantially parallel side walls, the sidewalls and inclined air inlet being positioned toward an upper side ofthe cooler housing, said inlet being rectangular, the at least twoevaporative cooling pads being mounted between the side walls adjacentthe inlet to cool air drawn into the housing via the inlet for dischargeof cooled air from an outlet of the housing.
 27. An evaporative coolercomprising: a housing adapted to be installed within a roof space of apitched roof, said housing having an air inlet associated with at leasttwo evaporative pads defining an air-permeable cooling means; means forsupplying water to each pad; and a fan for drawing external air into thehousing via the air-permeable cooling means and for discharging the airthereby cooled via an outlet from the housing, wherein the housing isconfigured so that the inlet is inclined in such a manner as to extendsubstantially parallel to a plane of the pitched roof with the inletlying closely adjacent to an external surface of the roof to avoid anysubstantial projection of the housing beyond the external surface of theroof; the air-permeable cooling means is mounted within the housing soas to be positioned substantially wholly beneath the level of theexternal surface of the roof; and the cooling pads define anair-permeable cooling means arranged within the housing beneath theinlet in an angular array, one inclined relative to another, to define azig-zag configuration.
 28. An evaporative cooler according to claim 27,further comprising means for supplying water to each pad, wherein theinclination of the individual pads within the zig-zag configuration issuch that water supplied by the water supply means to an upper edge ofeach pad will flow downwardly through the pad in a length directionthereof.
 29. An evaporative cooler according to claim 27, having withinan interior of the housing, means for removing water droplets which maybe entrained within a flow path of cooled air.
 30. An evaporative coolercomprising: a housing adapted to be installed within a roof space of apitched roof, said housing having an air inlet which is inclined in sucha manner as to extend substantially parallel to a pitched plane of thepitched roof when installed; at least one evaporative pad mounted in thehousing and defining an air-permeable cooling means associated with theinlet; means for supplying water to the at least two pads; and a fan fordrawing external air into the housing via the air-permeable coolingmeans and for discharging the air thereby cooled via an outlet of thehousing, wherein the housing is so configured that when installed withinthe roof space the inclined air inlet is closely adjacent the externalsurface of the pitched roof; the air-permeable cooling means is mountedto an upper part of the housing including the inlet, said upper housingpart being movable prior to installation of the cooler relative to alower housing part which includes the outlet, the movement between theupper housing part and lower housing part enabling the housing to beadjusted to suit a pitch of the roof into which the cooler is beinginstalled; the upper housing part is pivotally attached to the lowerhousing part to enable the upper housing part to be swung relative tothe lower housing part to adjust an angle of inclination of the upperhousing part to suit the pitch of the roof; and the upper housing partis sealed relative to the lower housing part by a flexible sheetmaterial which permits the relative movement between the upper and lowerhousing parts.
 31. An evaporative cooler according to claim 30 whereinthe flexible sheet material is of concertina like form.